Method and means for making air cooled cylinders



Feb. 27, 1934. c F. KETTERmG I 1,948,818

METHOD AND MEANS FOR MAKING AIR COOLED CYLINDERS Filed Sept. 15. 1950 '5a a Suva 144m;

Patented Feb. 27, 1934 1 UNITED STATES PATENT OFFICE METHOD AND MEANSFOR. MAKING AIR- COOLED CYLINDERS Application September 15, 1930 SerialNo. 482,005

5 Claims. (Cl. 11399) This invention relates to the art of makingaircooled cylinders and more particularly to the bonding of annular heatdissipating elements of high heat conductivity to cylinders of internal5 combustion engines. v

In the accompanying drawing in which like ref erence characters indicatelike parts throughout the several views,

Fig. 1 is a section thru an air-cooled cylinder l of a standard aviationengine;

Fig. 2 is a detached view of one, of the heat dissipating elementsutilized in this invention;

Fig. 3 is a plan view of a cylinder with heat dissipating elementsassembled and with clamps- 15 for temporarily holding the elements inplace;

Fig. 4 is a vertical section on the line 4--4 of Fig. 3; Fig. 5 is afragmentary vertical section on a larger scale than Fig. 4; and

Fig. 6 is a view of a device for setting and looking the clamps.

In this invention it is contemplated applying annular heat dissipatingelements of high heat conductive material such as copper to steel oriron cylinders such as the cylinders of radial aircooled airplaneengines in a manner to provide an uninterrupted metallic path for heatfrom cylinder to elements over the entire area between cylinder andelements.

In the drawing, 10 represents a cylinder barrel or'body, 11 a radiallyextending flange at the lower end thereof whereby the cylinder may besecured to an engine crankcase or base; 12 circumferentially extendingannular heat dissipating elements of copper or the like. Each element,which is of ring-like form, is composed of a radially extending heatdissipating flange or fin 13, substantially at right angles to agenerally cylindrical base flange 14 ,by which the element may be bondedto the cylinder. Ring-like element 12 as originally formed is divided asat 15 so that it may be contracted circumferentially into close contactwith the cylinder when applied thereto. These elements may be formedfrom thin sheet metal by a die-pressing and cutting operation andthereafter, or at any time before bonding, severed to produce the slit15.

Inv order to bond these elements to the cylinder barrel the base flangesmay be coated with flux and the elements threaded over the barrel whichmay have been coated previously with a suitable brazing material. Thepreferred brazing material is a thin sheet 16 of brass or the like whichhas been wrapped around the barrel as illustrated.

As shown in Fig. 4, a combined spacing means and clamp 17 may be placedupon the flange 11 after the brazing material has been applied to thebarrel. This clamp is preferably a contractible annular clamp shown asconsisting of three segments, each of which is provided with an end lug18 by means of which the segments may be drawn together to applypressure upon an annular heat dissipating element.

Either before or after the placing of the clamp on the flange 11 thefirst (lower) heat dissipating element is placed around the cylinderwith the base flange 14 in contact with the brazing material andextending between the cylinder and the inside surface of the clamp 17 asindicated near the bottom of Fig. 4. After the lower heat dissipatingelement has been applied the next one above it is similarly applied,another clamp 1'7 being placed on the top of the heat dissipating flange13 of the one already assembled; there after the next element is placedin the same manner as the one beneath it. Thus proceeding, all of theelements are assembled with the cylinder barrel and the clamps,theclamps completely filling the spaces between the flanges 13. There-30 after each clamp is set up so as to bind the heat dissipatingelements firmly to the barrel.

As shown in the drawing, channel members 19 embrace the several pairs oflugs on the segments of the clamps.- Each channel member is provided 5with set screws 20 each screw adapted to bear upon one lug of a segmentin such a manner that when said set screws-are screwed in' the adjacentlugs 18 of adjacent segments are drawn together whereby the annularclamp is contracted and the split ring-like heat dissipating element isbound firmly to the cylinder.

The assembly of the heat dissipating elements, cylinder, brazingmaterial and flux, is now very firmly and rigidly united so that theheat of the furnace to which it is tobe subjected in order to completethe bond cannot distort or cause displacement in any way of the elementswith respect to one another and to the cylinder.

The whole assembly may be dipped if desired 10o into a fluxing bath toprotect against possible oxidation in the heating furnace.

The heating furnace is preferably one which utilizes heat radiantly andis as free as possible from combustion products. The assemblies asdescribed are charged into this furnace and heated to a temperature of,say, 1800 F. sufficient to heat the iron cylinder and heat dissipatingelements to a red heat and fuse the brazing material in order to producethe bond. The process of brazing in general is that described in patentgranted to C. F. Kettering, May 1, 1928,

I claim:

1. -A method of bonding split annular heat dissipating elements to acylinder, each element having a heat dissipating flange and a baseflange at an angle thereto, which consists of applying said elements toa cylinder with brazing material and flux interposed, clamping eachelement to the cylinder independently of the others, then heating theassembly to a temperature sufficient to fuse the brazing material.

2. A method of bonding split annular heat-dissipating elements to acylinder, each element having a heat dissipating flange and a baseflangeat an angle thereto,'which consists of applying said elements to acylinder with brazing material and flux interposed, clamping eachelement to the cylinder independently of the others and filling thespace between the heat dissipating flanges, then heating the assembly toa temperature sufilcientto fuse the brazing material.

3. A method as defined in claim 1' in which each element is clamped bymeans of a divided clamp proportioned to fill the space between adjacentheat dissipating flanges.

4. Means for clamping a plurality of heat dissipating elements to acylinder in preparation for a brazing operation, said means comprising aplurality of annular clamps, each clamp consisting of a divided ringhaving a radial lug projecting outward from each of the adjacent ends,in combination with a channel member constructed and arranged to embracealined pairs 01' lugs of all of the clamps when the latter are arrangedadjacent one another in axial alinement with the lugs of the severalclamps cut substantially by a plane that includes the axis of theseveral annular clamps, and a plurality of adjustable devices carried bythe channel member, each adjustable device being constructed andarranged in cooperation with the channel member to force the radial lugsof one of the individual clamps toward each other and thereby contractsaid clamps independently.

5. Means for clamping a plurality of heat dissipating elements to acylinder in preparation for a brazing operation, said means comprising aplurality of annular. clamps, each clamp consisting of a divided ringcomposedof a plurality of arcuate segments, each segment having a radiallug projecting outward from each end, in combina-- tion with a pluralityof channel members equal in number to the segments, constructed andarranged to embrace alined pairs of lugs of all the clamps when thelatter are arranged adjacent one another with the lugs of each clamp cutsubstantially by planes that include the axis of the several clamps, anda plurality of adjustable devices carried by each channel member, eachadjustable device in each of the several clamps, respectively, beingconstructed and arranged in cooperation with the several channel membersto force the radial lugs of one of the individual clamps/toward eachother and thereby contract said clamps independently.

CHARLES F. KETTERING.

